This invention relates to circuit breaker arrangements which provide electrical protection, control and monitoring functions for medium voltage electrical power generation and delivery systems. In particular, this invention relates to circuit breaker arrangements that integrate and enhance the protection, control and monitoring functions required for electrical power generation and delivery systems.
Various prior art protection, control and monitoring disclosures describe concepts for achieving more enhanced and/or integrated protection, control and monitoring (PCM) for power delivery systems.
For example, the Mauthe U.S. Pat. No. 4,742,197 discloses a high voltage gas-insulated circuit interrupter which utilizes Rogowski coils to measure current at both ends of the interrupter. That patent describes a high voltage switch to which current measuring heads can be fitted by a simple arrangement in an easily accessible manner outside the region of the interrupter chamber. A Rogowski coil may be used in the measuring head and such measuring heads may be applied to high voltage circuit breakers and other switchgear.
The Baumgartner et al. U.S. Pat. No. 5,272,460 discloses a current and voltage transformer for a metal-encapsulated, gas-insulated high voltage switching installation having small dimensions capable of incorporation without problems at any point in the installation. A Rogowski coil is used for current measurement.
The Oishi et al. U.S. Pat. No. 4,237,520 discloses a gas-insulated switchgear arrangement which enables reduction of floor space for mounting and which is easy to install, maintain and inspect.
The Puccinelli et al. U.S. Pat. No. 4,644,438 discloses a current-limiting circuit breaker having a selective solid state trip unit providing circuit breaker contact separation by electro-dynamic repulsion toward the open position to effect current limiting when fault current exceeds a predetermined threshold. Rogowski coils may be used for fault current detection.
The Fernandez U.S. Pat. No. 4,799,005 discloses an electrical power line parameter measurement arrangement including compact, line-mounted modules. Current sensing provided by Rogowski coils is used for control and monitoring as well as in protection arrangements including bus and transformer differential. Relay systems actuated by the sensors operate circuit breakers to provide fault protection.
The Moncorge U.S. Pat. No. 5,552,978 discloses an arrangement for supplying a voltage to an electronic circuit, in particular an electronic circuit associated with a current sensor disposed on a high tension electrical line, to derive power from the current that passes through the high tension line. The power supply uses a torus provided with a magnetic core and a secondary winding to extract power from the line. A Rogowski coil is used to measure the line current.
The Blakely U.S. Pat. No. 5,652,507 discloses an arrangement and a method for measuring an AC current which saturates the core of a current transformer.
None of the prior art provides an arrangement for integrating protection, control and monitoring functions directly into a medium voltage circuit breaker design